The following description of background art may include insights, discoveries, understandings or disclosures, or associations together with disclosures not known to the relevant art prior to the present invention but provided by the invention. Some of such contributions of the invention may be specifically pointed out below, whereas other such contributions of the invention will be apparent from their context.
Wireless communication systems are constantly under development. Developing systems provide a cost-effective support of high data rates and efficient resource utilization. One communication system under development is the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE). An improved version of the Long Term Evolution radio access system is called LTE-Advanced (LTE-A). The LTE and LTE-A are designed to support various services, such as high-speed data.
Some new wireless communication systems such as the LTE based systems have adopted the use of Time Division Duplexing (TDD). LTE based systems may employ both TDD and Frequency Division Duplexing (FDD). In TDD, the same carrier frequency is used in the transmission and reception of data whereas in FDD, the different transmission directions are separated in frequency.
Typically, authorities allocate given frequency bands for a communication systems. In case of LTE based systems, different frequency bands are allocated for FDD and for TDD use. Each frequency band comprises multiple carriers. The traffic on adjacent carriers may cause interference. Especially in LTE based systems, where more than one network operator may be allocated carriers on the same frequency band. To allow flexibility, it is possible in LTE TDD to utilize different frame configurations in the transmission and reception. The number of uplink and downlink sub frames may be different in different frame configurations. If different operators on adjacent frequency carriers select different frame configurations, the uplink and downlink transmissions on adjacent carriers may cause severe interference. A large guard band may be needed to tackle the interference. The use of a guard band reduces spectral efficiency.